I made two small brackets from 1/4" balsa sheet to help support F1-T (top piece of F1 former) at the desired angle. I glued F1-T in place against the balsa brackets. I was then able to glue on the top sheeting. I used polyurethane glue for this sheet. Once it's dry, I will be able to sand the top sheet flush with the bevel angles on the sides of F1-T.